Reciprocating internal combustion engines include piston engines, rotary engines, and other well-known engine types. The specific field of this invention is, however, most directly to reciprocating piston engines.
In current engine designs of this type, a piston is used to drive a rotating crankshaft through a connection rod. The stroke of the rotating assembly is determined by the diameter of rotation of the crankshaft. This design leads to numerous limitations and deficiencies. First, at a given engine speed, the speed of the crankshaft ends remain constant. Thus, the duration of intake strokes, exhaust strokes, compression strokes and power strokes must remain the same. Second, power is produced by filling the engine cylinder with an air fuel mixture and inducing combustion of the mixture to generate heat and expansion to propel the pistons and, thereby, the crankshaft. Filling the cylinder with an air fuel mixture takes time. Power produced has, therefore, a direct correlation to the volumetric efficiency of the intake cycle. However, the time for the intake cycle is fixed by the rotational speed of the crankshaft and volumetric efficiency is often compromised. Third, completing the combustion process also takes time. In conventional engine designs, in order to compensate for the time it takes for complete combustion, the ignition timing is advanced ahead of the piston moving to top dead center (TDC) during a compression stroke. The higher the speed of rotation, the more advance in timing is required. This, in turn, wastes energy since additional energy must be expended in using the piston (during the compression stroke) to compress the expanding gases produced during the onset of the combustion process. This is completely wasted energy that could have been used to propel the crankshaft. Fourth, a method commonly used to compensate for the need for additional ignition time is to lengthen the connecting rod, thereby allowing the piston to “park” at top dead center for longer. However, there is a limitation to the length of the connecting rod used since longer rods will expand the physical size of the engine. Fifth, the power output of the convention engine design is directly proportional to the work generated by the expansion of the combusted fuel and air mixture. Since the time for the power stroke to transfer power to the crankshaft is dictated by the rotational speed, unused heat and expansible energy are channeled out when the exhaust valve opens near the end of the power stroke as the piston approaches bottom dead center.
Based on the foregoing, it is clear that there is a great need for additional flexibility in designing the pattern, speed and timing for various strokes in piston based internal combustion engines. However, there has been almost nothing done that is relevant to this goal. Moreover, there is no prior art where a piston interacts directly with an undulating flywheel surface. Only one patent known to the inventor might be argued to bear some relationship to an engine of this type: U.S. Pat. No. 3,745,887 issued to Striegl in 1973. Streigl has pistons that interact with a hollow cylindrical “rotor” having a cam edge. Each piston of the Striegl device is nested in its own individual hollow rotor with each rotor connected by an output/drive shaft to a flywheel. All of these elements are in axial alignment. However, there is nothing in Streigl or any other prior art known to the inventor that has off-axis pistons interacting with the undulating surface of a flywheel. Nor, does Streigl provide the additional design flexibility necessary for the truly efficient functioning of piston based internal combustion engines.